Truck cover assemblies are used to prevent material from escaping from open truck bodies, such as dump trucks or trucks carrying roll-off containers. Generally, these assemblies comprise a pair of tubular arms, which are pivotally attached at their lower ends to a frame of the truck body. An edge of a cover or tarp is attached to the upper ends of the arms. As the arms are pivoted from the front toward the rear of the truck, they draw the cover over the truck body.
Such tubular pivot arms are liable to bend and deflect, particularly on trucks and trailers over 19 feet in length. If the arms on either side of the truck or trailer do not bend and deflect by the same amount, the cover may roll or unroll unevenly, which may lead to premature tarp wear and ineffective covering and uncovering. This problem has been addressed by adding reinforcement to the arms by way of angle irons or vertical steel strips. However, angle irons make the arms excessively heavy. In particular, for pivoting mechanisms, which include a torsion spring mechanism for biasing the arm, the angle irons increase the stress on the spring mechanism, often to the point where performance of the spring mechanism becomes compromised. Additionally, adding a vertical strip of steel to the arms has a tendency to bow or twist the tubing from the heat of the welding process. This bow and/or twist is aesthetically unpleasant.